Hollow fiber separatory devices useful for dialysis, ultra-filtration, reverse osmosis, hemodialysis, hemoultrafiltration, blood oxygenation and the like are well known. While various methods of manufacture have been described, in general the resulting separatory element consists of a plurality of fine hollow fibers whose end portions are potted in a tube-sheet and whose open fiber ends terminate in a tube-sheet face which provides liquid access to the interior of the fibers. The separatory elements are sealed within a casing to form a separatory cell having one or more liquid ports which allow for the passage of one fluid through the fibers and another around the fibers without mixing of the two fluids. The separatory element may have two tube-sheets or a single tube-sheet, in which latter case the fibers are doubled back so that all the ends terminate together. The general configuration of the separatory element and separatory cell is similar to a tube-and-shell heat exchanger.
Patents representative of the art of hollow fiber separatory devices include U.S. Pat. Nos. 2,972,349, 3,228,876, 3,228,877, 3,422,008, 3,423,491, 3,339,341, 3,503,515 and the like.
In order for a tube-sheet material to be useful, it should adhere well to the fibers and yet not deform them. Further, it must be easy to handle and must fabricate into a strong unit. And, of course, it must be non-toxic when used in biomedical applications.
The prior art has used a number of resins to form the tube-sheets. Typical of such resins are polyolefins, wax-extended polyolefins, polyolefin copolymers, polyamides, polystyrene, polyvinyl chloride, silicone rubbers, epoxy resins and the like. However, all the above resins have been found deficient in one aspect or another, and the art to date has not found a generally acceptable tube-sheet material, particularly regarding medical applications.